Which automatic electric control shuts down the oil burner when steam pressure reaches a desired level?

The pressuretrol is the correct choice because it is specifically designed to monitor steam pressure within a boiler system and to control the operation of the oil burner accordingly. When the steam pressure reaches a predetermined level, the pressuretrol will automatically shut down the burner to prevent excessive pressure buildup, ensuring safe operation of the heating system.

In contrast, a limit switch primarily acts as a safety device that opens or closes circuits at designated temperature or pressure points, but it does not specifically monitor steam pressure for shutting down an oil burner. A thermostatic valve regulates the flow of fluids in heating systems based on temperature, but it does not directly shut down the burner based on steam pressure. Finally, a float switch is used in systems that manage liquid levels and is not applicable for controlling steam pressure related to an oil burner. Thus, the pressuretrol is the appropriate device for the function described in the question.